Is the word era the same in Brazilian and European Portuguese?

Yes

The word "era" is identical in meaning, grammar, and spelling in both Brazilian and Continental Portuguese. It functions either as the imperfect indicative form of the verb ser (to be) or as a noun meaning a long period of history (an epoch). The only difference lies in pronunciation. In Brazilian Portuguese, the vowels tend to be more "open" and clearly articulated. In Continental Portuguese, vowels—especially unstressed ones—are often more "closed" or even reduced/shortened in natural speech.

Brazilian Portuguese Examples

1. Eu era muito tímido quando era criança. (I was very shy when I was a child.)
2. Essa era a minha música favorita. (That was my favorite song.)
3. Ele era o capitão do time. (He was the captain of the team.)
4. Aquela era uma época muito difícil. (That was a very difficult time.)
5. A comida da minha avó era muito gostosa. (My grandmother's food was very tasty.)

Portuguese (Portugal) Examples

1. Eu era muito tímido quando era miúdo. (I was very shy when I was a kid.)
2. Essa era a minha música preferida. (That was my favorite song.)
3. Ele era o capitão da equipa. (He was the captain of the team.)
4. Aquela era uma época muito difícil. (That was a very difficult time.)
5. A comida da minha avó era muito boa. (My grandmother's food was very good.)